Modern Vespa

So,

Was on my way to work on Friday, started the PK125XL, remembered I needed some oil because fuel was low, shut it off and got the oil, got back, started it and got about 100m and then it died.

This time it is the spark that is gone. First instinct was to swap the plug but a brand new plug also had no spark. Looked at the connections to the ignition box next and they looked awful(bad crimps and kinked cables, no corrosion). Redid those today but still no spark.

It is not a dead short in the system, lights still work. The ground connection to the ignition box is also good.

Not sure what to look at next. Anyone know what the blue ducati ignition unit should ohm out too?

There is also a black cable that runs along the ignition wires that isn't connected on one end, anyone know what that might be and where it should go? Looks like it hasn't been connected ever based on the amount of oil and muck covering the terminal.

The ignition coil circuit is independent from the lights,horn, and brake circuits.

Stuck kill switch? Pictures of the junction box?

Order of things to try from easiest:
Pull the kill wire from the CDI.
Make sure the ends of the lead are screwed in tight.
Disconnect and ohm test the wires from the stator ignition coils (green to white, red to white). I forgot the acceptable range #'s but I'm sure others here do.
Replace the CDI.

Not really sure what junction box you are referring too, this was the most junction box thing I found, on the other side of the scoot though so not sure if it is related. It's an elestart model but no starter or battery is mounted.

Thanks for the advice going to ohm out the wires after work tomorrow and report back.
Which wire is the kill wire? Also not much to screw on on the CDI side so do they have screws on the ignition coil side?

Looks like the kill wire (from the key switch) on your bike grounds at the stator, vs the CDI.
The plastic junction box you're looking for is located on the swing arm on the right of the flywheel.
Green wire. Disconnect it there and see if it starts.
Long-shot, but easy to try.
The black wire from chassis, etc ground to the stator black wire should be connected there as well. Hopefully that isn't your dangling wire. It's a redundancy but an important one.

https://www.scooterhelp.com/electrics/wiring/PK_12V_elestart_w-ind.pdf

Pulled the green wire and that didn't help.

Resistance came out as:
White to red: 110ohm
White to green: 2.5ohm

White to green with the key to off: 0.00ohm

I think my stator might be busted? Couldn't find any values online but 2.5ohm seems very very low

Are you able to remove the flywheel and take a look?
0 ohms is a short, either the green wire (insulation damage, etc) or the ignition coil aka LT coil is cooked(?). Green wire stator to junction box could also be shorting somewhere in-between.
Pickup (red-white) is spot-on.
Good luck!

Green to white should read around 520ohms. For starters disconnect the round plug that's under the cover pointed in the pic below. That would take the kill wire out of the equation. Measure again green to white and see if anything changes. Next step is to check the green wire under the flywheel cause there's a chance the insulation disintegrated. If it's OK, the low tension coil is probably dead and it's new stator time or coil replace...

Alright, I'll check that after work today. Really hope I don't have to pull the flywheel as I don't have the tools to do so.

Going to order a flywheel puller and pickup coil together with my new exhaust if pulling that plug doesn't do it

Pulled that plug and it was the same so I am going to order parts today so I can hopefully fix this on Monday or something.

Finally got my parts!

Also found the "real" issue...

Should have just bought an entire stator but it was kinda expensive and I could only find them available in kits with a new flywheel and new ignition and it got pretty expensive.

The real issue is that all the wires between the coils have had their insulation rotted away. All the coils seem fine(haven't ohmed them all) besides the pickup one that reads 127 ohms but the previous idiot who was in here pulled new wires all the way to the stator and then spade terminaled them to the old shit wires

All the wires look cooked, cracked and corroded....

Going to replace all the wires tonight and put it back on and hopefully it will work

Put it all back together, tightened down the flywheel nut and it locked up the entire motor. I assumed I torqued it too hard so I backed it off and removed the flywheel again. Somewhere around there is when the woodruff key disappeared from reality. Spent 45min looking for it but couldn't find it.

New one is on its way, hopefully I'll have it on Friday...

Got it all put together and torque down last night and the spark is back and bigger than ever

Started and ran great, lights worked great ect...

Tried to take it to a gas station this morning, about 1/4 way the lights and fuel gauge part of the electrical stopped working

Might be as simple as the main fuse, it looked to be in horrible shape but I didn't have a multimeter on me to test it. My guesses are either that or one of my solder joints cracked. Hopefully it didn't short out the coils and burn up part of the stator...

Got it fixed, a solder joint on the stator cracked because of contamination. Cleaned up and remade it and it's working fine now!